Test i6

PPC i6 (ISix)
"external rf"

{0:r5=x; 0:r6=y;
 1:r5=x; 1:r6=y;
 2:r5=x; 2:r6=y;
 x=0; y=0;}

P0            | P1            | P2            ; 
li r8,1       | lwz r1,0(r5)  | lwz r2,0(r6)  ; 
stw r8,0(r5)  | xor r9,r1,r1  | xor r9,r2,r2  ;
              | li r8,1       | lwzx r3,r9,r5 ;
              | stwx r8,r9,r6 |               ;
              |               |               ;
              |               |               ;

locations [1:r1;2:r2;2:r3]
exists(1:r1=1 /\ 2:r2=1 /\ 2:r3=0)